With advances in technology, wireless communications protocols have become more sophisticated and demanding. Specifically, timing requirements related to communications between two wireless devices may be increasingly restrictive. For example, third generation and later cellular communications protocols may have tight restrictions regarding synchronization between a base station and a mobile terminal, such as a cell phone, a personal digital assistant (PDA), or the like.
In a continuous transmit system, such as a Wideband Code Division Multiple Access (WBCDMA) system, a mobile terminal may begin a continuous transmission in response to a command from a base station. The start of the continuous transmission may be timed, with tight timing requirements, from the receipt of the command. Due to latencies in the mobile terminal, there may be an error in the start of the continuous transmission. However, during the continuous transmission, the base station may send additional commands, which may adjust the timing of specific data in the continuous transmission. The specific data may be advanced or delayed to correct for any timing error in the start of the continuous transmission or to correct for subsequent timing errors; however, if the commands that adjust the timing of specific data introduce their own latency errors, then timing requirements may be difficult to meet. Additionally, the continuous transmission may be interrupted for a brief period to accommodate receive for monitoring purposes. It may be required for the continuous transmission to resume synchronously with the portion of the continuous transmission from before the interruption. Interrupting and resuming a continuous transmission is called a compressed mode.
A mobile terminal may include a baseband integrated circuit (IC) and an RF IC that communicate with each other using a baseband communications link. Receipt of a timing-related command may be received and down-converted by the RF IC, sent to the baseband IC over the baseband communications link, and processed by the baseband IC to create a transmit timing command, which is sent to the RF IC over the baseband communications link. The RF IC decodes and executes the transmit timing command to begin, adjust, or resume continuous transmission. However, uncompensated latencies or variances in latencies introduced by the baseband IC, the RF IC, or the baseband communications link may introduce transmit timing errors that cannot be corrected. Thus, there is a need to reduce the effects of uncompensated latencies or variances in latencies on the timing of data in a continuous transmission.